Transcriptional cell types in human erythroid cells from healthy subjects and Corfu deletion patients. (A) Double-label RNA FISH on cells from day 6 after hemoglobinization, probed with γ (green) and β (red) primary transcript, intron probes. Nine different transcriptional cell types are observed, representing every possible combination of γ and β signals. (B) Distribution of cell types from 2 healthy individuals. (C) Corfu heterozygous individuals: compound Corfu heterozygotes A01, A08, A09; simple heterozygote A07. (D) Corfu homozygous patients A02 and A06.